The pending U.S. application mentioned above, of which this application is a continuation-in-part, discloses and claims the use of a rapid response plasmatron for converting hydrocarbon fuels into hydrogen-rich gases. This process may be carried on-board vehicles.
Converting hydrocarbon fuels into hydrogen-rich gas (reforming) can be achieved with a plasmatron reactor. There are many advantages of using a plasmatron in the reforming process. Advantages include fast response (less than one second), adequate conversion into hydrogen-rich fuel, compactness (high hydrogen productivity), robustness (stable process), and the ability of the plasmatron to use many fuels, including hard-to-reform gasoline, diesel and biofuels.
For internal combustion applications, the hydrogen purity is not of great importance. High conversion efficiency into hydrogen is not necessary, since the low weight hydrocarbons that accompany the hydrogen produced by the plasmatron are also good fuels for use in internal combustion engines. More important is to minimize the energy consumed in the plasmatron during the reforming process.
U.S. Pat. Nos. 5,425,332 and 5,437,250 disclose plasmatron-internal combustion engine systems and the teachings of these two patents are incorporated herein by reference. Plasmatrons of the type used in the present invention are described in detail in these two patents.
Partial oxidation is a preferred method of reforming. An advantage of partial oxidation is that it eliminates the need for storing additional liquids on-board vehicles. Also, a fraction of the fuel is reformed in order to allow the introduction into the cylinder of an engine hydrogen-rich gas to improve the combustion process. Since the intention of the prior art is not to reform all of the fuel, the issues of efficiency, although still relevant, have not heretofore driven the design of a plasmatron system.
The previous application discloses the use of plasma catalysts on-board vehicles. The process of converting the hydrocarbon into hydrogen rich gases by the use of plasma catalysts addresses mainly the energy requirement in the plasmatron in the reformation process. Plasma catalysts, as used for applications in internal combustion engines, can decrease the electrical energy requirement. The prior art does not suggest the use of catalysts to maximize hydrogen yield nor to decrease the amount of CO (carbon monoxide) that is produced in the partial oxidation process (The hydrogen yield is defined as the ratio of the hydrogen in the reformate to the amount of hydrogen content in the fuel).
The prior art does not extend plasma catalysts into the context of fuel cell vehicles and stationary fuel cells in which very high hydrogen yields and low energy consumption are required.
The requirements on a reformate for fuel cell applications are very different from those for use of hydrogen rich gas in internal combustion engines. As described above, for application to internal combustion engines, it is not necessary to have high yields, a very efficient process or very clean gas. As used herein, clean gas is defined to be gas with small concentrations of CO, since CO is a poison to some types of fuel cells that are presently being considered for both stationary and vehicular applications, of which the PEM fuel cell is the most advanced candidate. U.S. Pat. No. 5,409,784 discloses plasmatron/fuel cell combinations and the teachings of this patent are incorporated herein by reference.
The prior art also does not disclose the possible use of water/steam in the reforming process.